Mechanical writing instruments of the propel-repel type comprise two inter-related tubes. One tube provided with the writing end is termed the body. The other tube removably secured to the body is termed, the top. The propel-repel mechanism may be located in the body or in the top. In either event, the lower end of the body tube is provided with the writing element which provides a closure member for the lower end of the body tube. The upper end of the body tube is normally left open and is constructed so as to removably secure the top to the body.
The lower end of the top tube is open and adapted to cooperate with the open upper end of the body tube so as to be removably secured thereto.
There has always remained a problem of what to do with the open upper end of the top tube. In some instances the top end is swedged over to close the top. In other instances, structures were built on to the top to provide fluid seals against ink leakage or to provide a fanciful end.
The mechanical writing instrument, when the body and top are fabricated from sterling silver or gold-rolled or gold-filled attached to a base metal is classed as an article of jewelry. The top must therefore present an esthetic appearance to provide sales appeal and a price beyond that of a lead pencil or inexpensive ball point pen.
Various types of plugs and configurations have been provided to close the top end of the top. Such plugs and configurations have then been used as symbols to indicate the source of manufacture and thereby have become trade marks. No consideration was given to the personality of the individual who ultimately purchased the article of jewelry for personal use.
In the prior application the ornament was held in the top end of the top by means of a shelf and a tapered side on the ornament so that a swedging action would taper the end of the top against the tapered side to provide a securing means. It seems that many people dropped the writing instrument or taped the top against a desk. Such action dislodged the ornament due to the delicate wall thinness of the top at the tapered section.